Abstract: We have studied the kinetics of the nitrogenase from A.vinelandii-230 and found that the nitrogenase is an allosteric enzyme.ATPis a positive effector for the nitrogenase while ADPa negative effector for the nitrogenase.ATPbinding sites are regulatory sites in the nitrogenase and the acetylene reduction active sites are catalytic sites in the nitrogenase.Between Av1 molecules and Av2 molecules, there are two or more than two binding sites among which possesses a positive cooperative effect, namely the effect between the Avl-Av2 binding sites and the acetylene reduction active sites.